I did advertise once to my c++ students that my feelings tell me that variadic templates are going to be key in implementing type lists in c++ template metaprogramming soon, and showed them a half-baked sketch. But they were not happy with that, “So, you have that class that depends on the type pack, very nice, now, how do you write a method whose signature is calculated out of your type pack?” they asked immediately. Such students’ questions brighten your teacher’s day, even if all you have to say at that point is “I’ll tell you next week”. So I will try in this post to work on the answer step by step.Read more of this post